Started with an adorable hardback book from Goodwill.
It had illustrations which I ripped out before I started cutting...
Now it's a box!
I used this tutorial:http://how2dostuff.blogspot.com/2006/02/how-to-make-secret-hollow-book.html
I made one change, though. My knife started to get dull so the edges were messy. I decoupaged the cut out pages on the inside of the box to cover up my mess.